At present it is common practice for the military services of various nations to transport stores, such as bombs, rockets and guided missles, by aircraft to selected locations. For obvious safety reasons such stores are carried on an aircraft in an unarmed or non-explosive condition, subject to being armed during launch to provide an armed or live store. Most stores are armed during their launch by pulling a lanyard from the store by means of a trigger unit having a movable lanyard pin about which the lanyard is looped. With the lanyard pin in the open position the looped lanyard falls with the store and the store is unarmed. With the lanyard pin being stationary (closed position) the loop is retained on the pin and the lanyard is withdrawn from the store so that an armed store is dropped. What is believed to be the most relevant prior trigger unit structure is shown in U.S. Pat. No. 4,266,462 which is incorporated herein by reference to better understand the structure and method of the invention described herein. It is to be recognized that other trigger units having a movable lanyard pin are also known. The prior trigger units had various disadvantages which are overcome by the structure and method of this invention. First, with prior trigger units it is possible, due to shock during a store launch, that the mechanism which unlatches in order to initiate release of a store may move back towards the latched position before the launch of a store is completed. Such movement could move the lanyard pin into its closed position before the loop has cleared the lanyard pin so that the lanyard is retained rather than released. It is also possible that the lanyard loop will be captively engaged by the lanyard pin moving towards the closed position to retain the lanyard and thus launch an armed store when the launch of an unarmed store is intended. Obviously the undesired launch of an armed store could have undesired results. Further, in securing the lanyard to the store during the period a store is attached to an aircraft it is not always possible to see whether the lanyard loop encircles the lanyard pin due to the store being in the line of vision. The lanyard latch mechanism must be set as a secondary operation after the lanyard loop is inserted into the triggering unit. Consequently, with at least some prior trigger units it is not possible to determine whether the lanyard loop is positioned for proper operation since no visual check can be made.